Cassandra Database Project Alireza Haghdoost, Jake Moroshek Computer Science and Engineering University of Minnesota-Twin Cities Nov. 17, 2011 News Presentation: Joab Jackson, “New Cassandra Can Pack Two Billion Columns Into a Row”, PCWorld News, January 2011.

What was the Problem ?  Facebook Messages Inbox Search  Feature that enables users to search through their Facebook Inbox  Millions of messages are sent everyday on Facebook  Messages stored in different data centers  How to handle indexing all of this information for Inbox search ? 2

What is Cassandra ?  Distributed storage system  Designed for managing kind of NoSQL database NoSQL: Key-Value, schema-less database  Scale to a very large size across many servers spread across different datacenters small and large components fail continuously  No single point of failure Data replicated at several nodes 3

Cassandra Goals  High scalability  The ability to scale incrementally  High performance  The ability to respond quickly  High availability  The ability to retain data available for users 4

Cassandra Data Model  Cassandra does not support a full relational data model  Key-Value data model  Every row is identified by a unique key  Every row can have unlimited number of Columns classified in different columns family can pack Two Billion columns into a row  Columns are sorted in a row by name order time order (required for inbox search) 5

Distribution and Replication  Data is distributed across the nodes using Consistent Hashing function  High availability is achieved using replication  If one storage node fails, data that has been replicated in other nodes is available.  Data replicate at N node across data centers actively.  Replication policies: Rack Unaware Rack Aware Datacenter Aware 6

Users of Cassandra System  First deployment:  2008 by Facebook, inspired by Google and Amazon  Designed for message inbox search system  Stores TB’s of indexes across a cluster of 600+ cores and 120+ TB of disk space  Each node can handle over 5,000 requests per second  Well-known users: 7

References  Prashant Malik, “Inbox Search”  Joab Jackson, “Apache Cassandra Ready for the Enterprise”,  Joab Jackson “, New Cassandra Can Pack Two Billion Columns Into a Row  Avinash Lakshman and Prashant Malik. “Cassandra: a decentralized structured storage system” SIGOPS Oper. Syst. Rev. 44, 2 (April 2010) 8

Thank You 9